In the rubber industry, when producing a rubber composition containing filler such as carbon black and the like, it is known to use a wet masterbatch in order to improve processability of the rubber composition and dispersibility of the filler.
By producing a rubber composition by using the wet masterbatch, there is obtained a rubber composition having better dipersibility of the filler and better rubber physical properties such as fatigue resistance, reinforcing property, and the like compared to a conventional rubber composition obtained by mixing in a solid phase.
Further, by using such a rubber composition as a raw material, there can be produced rubber products such as tire and the like having, for example, reduced rolling resistance, and excellent fatigue resistance and abrasion resistance.
Such a rubber wet masterbatch is obtained in the following manner.
First, filler-containing slurry is obtained by mixing beforehand the filler and a dispersion solvent in a certain proportion and dispersing the filler in the dispersion solvent by a mechanical force. Subsequently, the filler-containing slurry and a rubber latex are mixed in a liquid phase, followed by addition of a coagulating agent such as an acid and the like to coagulate the mixture, and the coagulated material is recovered and dried to obtain a rubber wet masterbatch.
Furthermore, as another method, there has been proposed a method of producing an elastomer composite, which is strongly bound without using a coagulating agent including acids and salts, by feeding a fast flowing particulate filler and a slow flowing elastomer latex to a mixing zone of a coagulated rubber reaction vessel, and mixing and coagulating the mixture under a state of a high shear flow and a turbulence flow generated in the mixing zone (see Patent Literature 1).